Monday, 13 April 2015
Recent Studies on the Role of Sleep
As Evan Thompson, a philosopher of biology and the mind, stated in a recent lecture, our Western way of life is so focused on productivity as a dominant value that when we go to bed, we are so exhausted that we literally “crash” into sleep. As a result, we very often do not even experience the special state of consciousness known as hypnagogia, which normally occurs during the first phase of falling asleep. When someone is in this state, they are still sensitive to sensory inputs from the outside world, but no longer entirely awake, and they are more likely to make all sorts of original mental associations.
In addition to watching Thompson’s lecture (see first link below), you may want to read Waking, Dreaming Being (the book on which the lecture is based, published in 2014), or his earlier, very rewarding book, Mind in Life (2007).
And if you want to dig a little deeper into the question of the brain structures associated with sleep, the third link below points to a study published in February 2014, about a controversy that Thompson discusses in Waking, Dreaming, Being. This study showed that people who frequently recall their dreams have different resting brain activity patterns from people who do not. This finding tends to confirm the hypothesis that there is a system in the prefrontal area of the human brain that contributes to dreaming and whose activity is distinct from that of the region of the pons that stimulates the cortex, which is still the prevailing hypothesis on this subject.
Another interesting sleep study was reported in Science magazine in June 2014. This study confirmed the role of sleep in the structural consolidation of interneuronal connections after learning has occurred. More specifically, this study of the motor cortex of mice showed how sleep promotes the formation of postsynaptic dendritic spines on a subset of dendritic branches of individual layer V pyramidal neurons. These results clearly imply that sleep plays a role in memory.
Evan Thompson: “Waking, Dreaming, Being” at CIIS
Waking, Dreaming, Being
Resting Brain Activity Varies with Dream Recall Frequency Between Subjects
Sleep promotes branch-specific formation of dendritic spines after learning